Linear measuring device



United States Paten 3C? Paul P. Gottschall and Chauncey L. Grebe, Concord,

Calif., assignors to United States Steel Corporation, -a corporation of New Jersey 1 Y Filed June 11,1957, No 664 v; t 6 Claims. (11. ass-219$ M This invention relates to an improved de vice for'vis n. ly indicating a'linear dimension of moving articles.

The device is particularly useful in'a shear line in which a flying shear cuts continuous strip into individual sheets, where the device furnishes an'imniediate indication of the length of each sheet. Thus the device enables an operator to make minor adjustments in the shear mecha'-' nism to assure that it cuts sheets accurately'to 'the de-" sired length. Nevertheless, the device has general appli-" cation for checking a linear dimension of articles moving along a conveyor or the like, an'dthe invention isfn'ot limited to use in any specific'envir'onment- An object of the invention is to provide an improved measuring device which utilizes instantaneously responding electronic means for'indicating a-dimension of each article in a rapidly moving line of articles withoutinterfering with their movement. I

A further object is to'p'rovide'an improved measuring device which affords the foregoing advantages and which displays each indication long enough for an operator to ascertain whether it is within the prescribed range and then automatically resets itself for measuring the next article;

A more specific object is to provide anim'proved measun'ng device which includes an electronic pulse counter, photoelectric means responsive to the'pas'singof one edge of an article for transmitting a series of pulses to said counter, photoelectric trigger means responsive to the passing of the other edge for-blockingfurther-pulses," and photoelectric means responsive to the passing of'an edge of the next article for resetting the counter, the

pulse count furnishing an' indication of a dimension-of the article. t

In accomplishing these and in our device; and t 1 t Figure 4 is a top plan view-of the reset head embodiedtherein. a ,7 a t Figure 1 shows a portion of a'shearline which*in-' cludes a conventional-flying shear10, a power'driven' belt-type conveyor 12, conventional upper and lower magnetizable rolls 13 and 14'at the exit end of said conveyor,

and conveyors 15 and 16 beyond said rolls. A continu ous strip S, in this instance of magnetic material, feeds into the shear which cuts it into individual-sheets S The conveyor 12 carries sheets S "away from i the shear and travels slightly faster than the uncut strip to space the sheets a few inches apart. Normally the upper roll 13 is magnetized and the lower roll'14- demagnetized to direct prime sheets to conveyor '15, .but this relation other objects of the invention, we have provided improved details of struc can bereversed through suitable control means not Shown to directdefective sheets to conveyor 16 This 1 ofits belts. V Light sources 20, 21 tand 22 are mounted:

structure constitutes a typical environment in which the device of our invention can be used, but is not part of our invention and hence is not described in greater detail. 7

In accordance our invention fa photoelectric measuring or pulsing head; l'l a photoelectrictrigger .head 18 and a photoelectric reset headi19 are mounted under;

the carrying flight of conveyor 1 2 fiush with the surface above the conveyor in positionsto cast light beams at therespective heads 17; 18 and 19; The measuring head 17, is mounted for adjustmentlongitudinally of the con-- veyor near. the entry end .thereo f.-, The trigger head 18 v is spaced beyond the measuring head a distance approximately 7 equal to a sheet length, as hereinafter explained. 1

The reset head 19 is spacedbeyond themeasuringhead a distancesomewhat less than asheet length.

As shown inFigure 2, the measuring head.17 includes an opaque case 23, in the upperface ofuwhich are mounted a plurality 20f alternating. transparent windows 24,and opaque separators 25. In the illustration thereare ten windows and-nine,- separators, each having a thickness of about 0.007;:inch. sThtiaWindOWS -,CO.]JV6I1= iently are .of a plastic; materialsuch as thatsold un der the trade, name ,iLuciteQwhile,the separatorstcan ber of brass shim stock. As the trailing edge of a sheet moves over the measuring .head the windows are exposedsuccessively, to..light from the. source 20,..wherebythe. in-.

' tensity .of lightadmitted to the'interionofathe .case 23' increases in steps corresponding in number to the number-of windows. The case :houses ahmultiplierflphotou tube 26, such as the type commonlydesignated 93-1A,

which transmitsa pulse with each light increment.- -'-The multiplier phototube is connected to a conventional amplifier 27and thence to aconventional 'pulse'counter 28', such as that -known as a Berkeley Dual 'Pr'eset Electronic Counterf -The counter includes an indicator 29 for showing the number of pulses received" during any-interval-in which it is set for counting. e

' As shown in Figure-3, the trigger head 18 includes an opaque case 39, wh'ose upperface contains a single narrow window 31, preferably similar to one of the windows 24. -The'case 30 housesa phototube 32, which-is connected through aconventional amplifier 33 to-a con-' ventional flip-flop or bistable multivibrator '34." As shown in Figure 4, the reset head'19 includes an'opaque case 35, whose upper face contains a window 36j This last window conveniently can be somewhat wider than the windows in the measuring'and trigger heads 17 and Figure 3 is a top plan view of'the trigger head'embodied 18. The case 35 houses a phototube 37,'which is connected through a conventional amplifier 38' to the nipflop 34p 7 As is well knownin the art, a'fl-ip-flop has 'two stablecurrent-conducting conditions and it can be changed fromone tohhe other by an outside stimulus." 'In'our" device the current conduction path through'the fiip-flop 34 changes whenthe leading'edgeof a sheet S passes over'the window 31 of theit'rigg'er head 18 andchan'ges" back when 'the leading edge" of'the 'next sheet' 'passes 'In each in'-' over the window 36 of the'reseflhead 19 stance the resulting loss'of conduction through the phototube 32 or 37 'acts' through the respective amplifier 33 or 38 to furnish the external stimulus for changingthe counter-28 forisup'plying a blocking voltage andanother connection 40-thereto forsupplying reset pulses. When the currentconduction path changes in response'to the leadingedge of a sheet passing over the trigger head 18,

"'1 the flip-flop commences to transmit a negative block- I 2,941,086 Patnted Junefllfl, 1960 Koulicovitch Aug. 20,1946 Hillier Jan. 10, 1950 Clark Oct. 30, 1951 Woodland a a1. Oct. 7, 1952 5 Hartwig May 26, 1953 6 Wagner Nov. 16, 1954 Caldwell Apr. 19, 1957 Koulikcvitch Aug. 26, 1958 FOREIGN PATENTS Germany July 15, 1954 

